| 摘要 |
The method and the device arc used for the cryogenic decomposition of air in a distillation column system for separating nitrogen and oxygen, said system having a first high-pressure column (23), a low-pressure column (25, 26), and three condenser-evaporators, namely a high-pressure column head condenser (27), a low-pressure column bottom evaporator (28), and an auxiliary condenser (29; 228). |
| 主权项 |
1. A method for the cryogenic separation of air in a distillation column system for nitrogen/oxygen separation that comprises a first high-pressure column (23) and a low-pressure column (25, 26) and also three condenser-evaporators, namely a high-pressure column overhead condenser (27), a low-pressure column bottoms evaporator (28) and an auxiliary condenser (29; 228), in which method
a first feed air stream is cooled in a main heat exchanger (20, 21), the cooled first feed air stream (22) is introduced at a first pressure into the first high-pressure column (23), in the high-pressure column overhead condenser (27), gaseous overhead nitrogen (44, 45) from the first high-pressure column (23) is condensed, at least one portion (47) of the overhead nitrogen (46) condensed in the high-pressure column overhead condenser (27) is applied as reflux liquid to the first high-pressure column (23), one portion of the bottoms liquid (66) of the low-pressure column (25, 26) is evaporated in the low-pressure column bottoms evaporator (28) in indirect heat exchange with a condensing heating fluid (58), an unevaporated portion (67) of the bottoms liquid (66) of the low-pressure column (25, 26) is at least partly evaporated in the auxiliary condenser (29; 228), and at least one portion of the liquid (68) evaporated in the auxiliary condenser (29; 228) is obtained as a gaseous oxygen product (69),characterized in that
the distillation column system for nitrogen/oxygen separation further comprises a second high-pressure column (24), a second feed air stream is cooled in the main heat exchanger (20, 21), the cooled second feed air stream (35) is passed into the second high-pressure column (24) at a second pressure, which is higher than the first pressure, and at least one portion of the overhead gas (58) of the second high-pressure column (24) is used as heating fluid in the low-pressure column bottoms evaporator (28). |
